Flow control valve



Dec- 1, 1964 R. K. scHREcoNGos-r ETAL 3,159,375

FLow CONTROL VALVE Filed May 31. 1962 I5 Sheets-Sheet 1 OQTToraMaYf Bec.l, 1964 R, K. scHREcoNGosT ETAL 3,159,375

FLow CONTROL. VALVE Filed May 31, 1962 :5 sheets-sheet 2 Dec. 1, 1964 R.K. scHREcoNGosT ETAL 3,159,375

FLOW CONTROL VALVE .'5 Sheets-Sheet 3 Filed May 31, 1962 United StatesPatent O pas 3,159,375 FLDW CNTRL VALVE a Richard K. Schrecongost and.Foei A. .lannangm Rotentrord, lll., assignors to Greenlee Bres. fr Se.,Rockford, ill., a corporation of illinois Filed May 3l, 1h62, Ser. No.198,939 2 Claims. (Qi. 25E-31) The invention relates to hydraulic ilowcontrol valves of the type which may be used in die-casting machines tocontrol the stroke of a hydraulically actuated injection plunger.

The primary object of the present invention is to provide a novel valveof the above character with which the plunger velocity during theinjection stroke may be increased in a plurality of precisely controlledand adjustable steps preselected according to the characteristics of themetal being cast and the size and shape of the die cavity being used.

Another object is to provide a unitary ilow control valve capable ofinitially accelerating the plunger at a controlled rate until the metalcylinder has been closed, advancing the plunger into the metal cylinderat a selected constant velocity during. the die-filling portion of theinject1on stroke thereby providing a steady flow of metal into the die,and sharply accelerating the plunger at a preselected iinal rate so thatthe plunger closes at high speed.

The invention also resides in the novel construction and mounting of thevalve operator whereby the steps in the valves opening may be adjustedprecisely as desired and independently of each other so that the plungerspeed and acceleration during each step may be selected exactly to titthe characteristics oi the metal and the die.

Other objects and advantages of the invention will become apparent fromthe following detailed description taken in connection with theaccompanying drawings, in which:

FIGURE 1 is a fragmentary elevational view of parts of a die-castingmachine embodying the novel features of the present invention with partof the dies and the injection cylinder broken away and shown in section.

FIG. 2 is an enlarged fragmentary end elevation of the control valveassembly.

FIG. 3 is a fragmentary sectional view taken along the line 3-3 in FIG.2.

FIG. 4 is a diagrammatic view showing the hydraulic circuit of thedie-casting machine.

FlG. 5 is a graphic representation of the velocity of the plunger duringdii'rerent portions of the injection stroke.

As shown in the drawings for purposes of illustration, the invention isincorporated in a die-casting machine for injecting molten metal into amold and holding the metal under pressure as it solidiics, the moldbeing formed between two die members lil releasably clamped together ina manner well known in the art. -The illustrative machine is of the coldchamber type in which the metal is ladled through a port or well lllinto a bore 1.2 forming the metal cylinder leading to the die cavity,and a hydraulically actuated plunger i3 slides back and forth in thebore to force the metal into the die cavity.

The plunger 13 is carried by a piston 14 tted in an injection or shotcylinder l5 axially alined with the bore 12. To reciprocate the plunger,pressure fluid is delivered alternately to opposite ends of the cylinderl5 from a suitable source, herein an accumulator 17 of conventionalconstruction and operation charged by a hydraulic pump (not shown) andcapable of storing a large volume of oil under pressure vfor delivery tothe injection cylinder. Connecting the accumulator to the head end ofthe cylinder l5 is a passage deiined by pipes 1.8 and 19 (FlG. l), andinterposed in the passage is a valve assembly 2t) for Finally, as theplunger approaches the end of its stroke,

li Patented Dec. l, 1964 selectively opening and closing the passage tooperate the plunger.

Herein, the valve assembly Ztl includes a generally cylindrical Valvehead 2l slidable back and forth between an open position and a closedposition in a cylindrical chamber 22 formed in a valve body 23, thechamber havinfr an inlet port Z4 through one side communicating with theaccumulator and an open end 25 forming an outlet port connected to thepipe i9 leading to the injection cylinder. Ahelically coiled compressionspring 27 is conned in the chamber 22 between the closed end 2S thereofand the valve to urge the latter toward the port 21S so that a nozzleend 29 of the valve extends into the port 25 amd an annular beveledshoulder 3) encircling the valve seats in the outlet. When the valve isin this closed position (FIG. 3), oil is pumped into the accumulatorthrough an annular chamber 31 around the valve communicating between theinlet port 24 and a conduit 32 leading to the pump.

After a charge of metal has been introduced into the bore, the valve 2lis shifted to the right, as viewed in FIG. 3, to open the ports 24 and25 and permit oil to flow from the accumulator into the injectioncylinder 15 and shoot the plunger 13 into the bore l2 and past the welllll, closing the latter and forcing the metal into the die. The nozzlemay be grooved 'as at 33 (FIG..3) to obtain a controlled ilow throughthe port 25. vTo retract the plunger and open the well for the nextcharge of metal, oil is directed into the rod end of the cylinder l5through a line 3d. The dies are opened for removal of the completedcasting and then closed for the next' injection stroke of the plunger.

The present invention contemplates a novel valve assembly Zil foropening the passage between the accumulator and the injection cylinderin a plurality of controlled steps whereby the velocity and accelerationof the plunger i3 during dierent portions of the injection stroke may bepreselected according to the characteristics of the metal being cast andthe shape and size of the casting. For this purpose, the valve assembly2i) includes a hydraulic valve actuator capable of moving the valve 2lrstat a controlled rate of travel into a preselected partially openposition thereby steadily increasing the rate of iiow of oil into thecylinder l5 and correspondingly accelerating the plunger at apreselected and controlled rate until the well is closed. Then, byleaving the valve in the partially open position, the plunger may beadvanced for a short period at a constant rate to provide a steady,-predetermined iiow of tluid metal into the die cavity to ll the latterat a rate adapted to the type of metal and die.

the valve may be moved farther toward the open position, again atapreselected rate of travel and again increasing the rate of flow to theinjection cylinder to accelerate the plunger. This iinal accelerationmay be at a greatly increased rate to impart a high closing velocity tothe plunger. Also, the valve may be stopped short of the fully openposition to control the final plunger velocity.

To achieve these ends, the valve actuator includes a reciprocatingelement, herein a piston 3'7slidable in a .cylinder 3S, connected to thevalve to shift the latter toward the open position, and pressure meansincluding v iiow control means isprovided to regulate the rate of travelof the piston 3'7 and, therefore, to control the rate of acceleration ofthe plunger i3. A stop member 39 is disposed in a preselected blockingposition to block sliding o the piston 37 when the latter has moved thevalve to the partially open position, the stop 39 thus determining thevelocity of the plunger during the filling portion of the stroke.Selectively operable means is provided to move the stop out of theblocking position when the plunger approaches the end of its stroke sothat 'thepiston 37 vmoves the valve past the partially open positionthereby to increase the iiow of oil to the plunger and shoot the latterforward at high'speed. Preferably, a first flow controller il regulatesthe initial plunger ac- Celera-tion and a' second flow controller al,activated when the stop 39 is moved, controls the iinal rate of travelof thepiston 37 and thereby regulates the nal accclera- Y tion of Vtheplunger. A second stop 42 may be provided to block opening of the valveat a second predetermined point thereby determining the open positionand the highest fluid flow Vduring'each injection stroke.

Herein, the cylinder 38 is formed in the valve body 23 adjacent theclosed end 23 of the chamber 22 and preferably is coaxial with thechamber, and a rod 43 extending through rand journaledfor endwisesliding in the coinrnon wall V44 between the cylinder d8 and the chamberrigidly joins the'piston 37 and the valve for sliding back and forth inunison. The spring 27 is coiled around the rod 43 and urges the piston37 into its normal, retracted Vpositioi'if'a`r'ija.ce'i:t the wall i4and against the end of a collar integral with the wall 4d and encirclingthe rod to provide the bearing for the rod. Seal rings d encirclingv therod within the bearing prevent oil leakage through the wall.

The pressure means lfor moving the valve toward the Open position at acontrolled rate include, in this instance, a conduit 47 for deliveringpilot pressure iluid to the cylinder 38 to move the piston 37 away fromthe end wall,

"'while pressure fluid trapped within the chamber 22 resists 'movement'of the piston away from the wall, the iiow controller 40 comprising anadjustable needle valve interposed in a drain line 48 communicating withthe chamber through conduit 49 to restrict the ow of vtrapped fluid'from the chamber and thereby retard the movement of 'the piston 37 andvalve 21'. By adjusting the needle to increase or decrease the ilowthrough the lines i9 and d, the rate of travel of the piston during thisstep and, ac- 'cording1y,A the acceleration of the plunger, arecorrespondingly increased or decreased. It will be apparent that lluidcould be coniined within the head end of the cylinder 38 with the sameresult. In the illustrative embodiment, however, this end of thecylinder communicates with'the outlet port 25 through a vent line Sliextending through the rod to maintain a balance of pressure atoppositeends of the piston assembly.

Shown in FiG. 5 is a graphic representation illustrating one combinationof steps obtainable with the novel Y valve assembly. In the graph, thevertical coordinate represents bothV the velocity -of the plunger andthe volume of flow into the injection cylinder, the two being directlyproportional. The initial acceleration is represented in FIG. 5 bytheslope of the line 51.

In this instance, a second hydraulic actuator comprising a piston rSZslidable in a cylinder 53 disposed in endto-end relation with thecylinder 3S and preferably coaxial therewith is formed in the valve body2x3 to provide rselectively operable means for moving the stop 39 intoand out of its blocking position. As shown in the drawings, the stop maybe formed by'a rod 54 extending through the partition 55 between thecylinders 3S and SS-and preferably fastened at one end to one of thepistons with the other end terminating adjacent the other piston,

the free 'endY thus coacting with the adjacentpiston to'i'orm.

theV stop 39. Herein, thefrod is secured 'to the vpiston 52 with thefree end spaced a short distance from the piston `37 to abut against thelatter and interrupt its movementV piston 37 at a second point.

der is maintained and the plunger is advanced at a constant Velocity, asindicated by the line 53 in FIG. 5.

Movement of the rod 5d out of the blocking position is accomplished bydelivering oil under pressure to the rod end of the cylinder 53 througha conduit 59 thereby to shift the piston 52 to the right as viewed inFIGS. 3 and 4. The' second'flowcontroller il activated when the stop 59ismoved out of its blocking position herein comprises a second needlevalve interposed in a normally closed drain line olwhich is connected inparallel with the line 48 and is opened when the stop 39 is moved. Toprovide a rate of plunger acceleration different from the initial rate,the needleydl may be set to accommodate a greater volume of dow from thechamber 22 than does the needle dit. Accordingly, the piston 37 andvalve 2l will move to the right at af'faster rate than before therebycompleting the filling of the `die and compacting of the metal at highspeed. When the needle 4l is left completely open, a sharp increase inplunger speed is obtained as indicated at di in FlG; 5. A differentsetting of the needle dll will eiiect an increase in accelerationgreater than the initial rate yet less thanV instantaneous, this beingindicated in phantom at e2. in the graph.

if the valve 2l is moved to the fully open position, the full capacityof the system will be delivered to the injection cylinder. l lf, on theother hand, a lower 'plunger speed than'the highest obtainable is calledfor by the characteristics of the metal and the die, opening of thevalve may be limited by interrupting movement of the ln this instance,the stop 42 utilized for this purpose is formed by a rod 63 extendinginto the cylinder 53 through the rod end thereof and having a free 'enddisposed adjacent and in thepath of the piston 52 to abut against thepiston after the latter has shifted the stop 39 a predetermined distanceaway from the piston 37. in this'manner, the level of the line 64 (FIG.5) is determined. i

The invention also contemplates constructing and mounting the valveactuator in a novel manner so that each of the steps inthe opening ofthe valve may be adjusted precisely as desired and independently of theother adjustments and, therefore, the plunger velocity during eachportion of the injection stroke may be selected exactly to iit thecharacteristics of the particular metal and the die. To these ends, thepiston 52 is adjustable relative to the piston 37 to adjust the stop 39andV vary the stroke of the piston 37 thereby to select the partiallyopen position of the valve 2l, and the stop d2 is adjustable toward andaway from the piston 52 without disturbing the setting of the stop 39. l

For these purposes, the cylinders 3S and 53 are formed in a hollow,open-ended sleeve 65 divided intermediate its ends by a transverse wallforming the partition 55, and the sleeve is telescoped into acylindrical recess o7 in the valve body so that Vthe inner end of therecess forms the end of the cylinder 3S against which-the piston 37normally abuts. To adjust the stop?, means is provided to shift thesleeveV axially in the recess and maintain a selected position of thesleeve therein thereby to shift the partition and the piston 52 towardand-away from the piston 37. ln this instance, this means comprisesthreads 63 around the exterior of the sleeve and in the wall of therecess.

Turning of the sleeve to shift the stop k39 back and forth to adjust thestroke of the piston 37 may be accomplished conveniently by'a hand wheelo9 fixed to a hub 7o formed integrally with the outer end of the sleeve.To lock thesleeve in a selected position, a-collar '71 is telescopedloosely around the sleeve for abutment with the hubV and'is releasablysecured to the sleeve by a radially extending pin 72 urged by a'spring73 into one f of a plurality of bores 74 angularly spaced around theposition. 'With the valve held in this position, a constant vvolume flowfrom the accumulator to the injection cylinsleeve. A knob '75 isprovided to disengage the' pin thereby permitting turning 'of the sleeverelative -to the collar. rthe collar 7l isloclred against turningrelative `lto the valve body by means of an axially extending dowel pin77 with opposite ends seated in registering bores in the collar and inthe body, the pin 77 being urged Itoward the collar by a compressionspring 78 confined in the bore 79 in the body. Thus, as the sleeve isshifted in and out, the spring 7S extends and contracts to press the pin77 into the collar and, therefore, holds the latter firmly against thehub 701.

As shown in FlG. 3, an indicating finger Sil may be fast on the body 23to project axially over the collar 7l, and the latter may be marked withcalibrations to indicate the amount of axial adjustment of the sleeve.When a desired adjustment has been made, the sleeve is locked in placeby seating the pin 72 in the registering one of the bores 74 in thesleeve.

The passages S7 and 59 opening into the cylinder 53 on opposite sides ofthe piston 52 communicate respectively with axially spaced annularchambers Sl and 82 encircling the sleeve. These chambers are made ofsubstantial axial width to maintain communication with conduits 83 andS4 in the valve body in any of the various axial positions of the sleeverelative to the body.

Closing the outer end of the sleeve 65 is a plug S5 telescoped into thesleeve and having an annular ange S7 for abutting against the hub 79 andreceiving bolts 88 (FIG. 3) which are threaded into the hub to hold theplug SS in place. Thus, the inner end of the plug forms the end Wall atthe head end of the cylinder 53. rl`hestop rod 63 extends axiallythrough the plug and into the cylinder and herein is threaded at 89 inthe plug thereby providing means for adjusting the stop d2 toward andaway from the piston 52. A hand wheel du is keyed to the outer end ofthe rod 63 to facilitate turning of the latter, and a collar 91 (FIG. 3)is disposed around the rod and in abutment with the wheel @il Thiscollar is releasably locked to the wheel by a pin 92 which may bedisengaged by a knob 93, and a pin 9d locks the collar 91 againstturning relative to the hub 76. A finger @5 extends over calibrations onthe collar 9i to indicate thev amount of adjustment of the stop 42.

With this arrangement, the operator irst adjusts the stop 42 bydisengaging the pin 92 and then turning the wheel in the appropriatedirection until the end of the rod 63 is disposed the desired distancefrom the piston ,52. Then the -pin 92 `is locked in the collar 91 `andthe position of the stop 42 is thereby fixed. Then the pin 72 isdisengaged and the wheel e9 turned until the desired increment of changein the position of the stop 39 has been made, as indicated by theposition or" the finger Sti relative to the collar 71. lt will beapparent that both the piston 52 and the stop 42 move in unison with thesleeve 65 thereby maintaining the first adjustment. When the pin 72 islocked in the sleeve, the strokes of the pistons 37 and 52 aredetermined. The number of settings for each stop is limited only by thelocking means, in this instance the spacing of the recesses engagedbythe pins 72 and 92.

Operation The novel features of the present invention will be apparentfrom the following summary of the operation of the valve assembly abovedescribed as controlled by the hydraulic circuit shown in FIG. 4.

Initially, the stops 39 and 42 are adjusted as above described and thehow-controlling needle valves d@ and 41 are set to provide the desiredow of trapped fluid from the chamber 22 during acceleration of theplunger. With the valve 2l closed, a Vsupply of fluid under pressure isstored in the accumulator 17 to operate the plunger'.

Herein, solenoid-operated pilot valves 9d and 97 are provided to controlthe operation of the valve actuator. As will be seen from FIG. 4, .pilotvalve 95 controls the movements of the piston 37 and pilot waive @7controls the piston 52. When the plunger is at rest, the solenoid 98 isde-energized and the spool 99 of valve 96 is springd urged to the leftto connect the'conduit 49 to a pressure line lll@ through check valvelill, While the conduit 47 connects the cylinder 3S to the reservoirthrough drain lines N2 and 163. The spool 14M of de-energized solenoid jconnecting pressure line ldd to the conduit i7 leading to v the rod-endof the cylinder 3S. At the same time, the chamber 22 is connected to thedrain line 193 through the line iSv-controlled by the needle valve 4t?,the parallel line d0 being closed by the pilot valve 97. Thus, thehead2l is moved toward the open position at a rate of travel determined bythe settingof the needle 4? until the piston 37 abuts against the rod54. Preferably, the stop 39 is positioned so that this occurs after theplunger i3 has closed the well ill. Thereafter and until the stop 39 ismoved, the plunger advances into the bore at a constant velocity,yielding of the piston 52 being prevented by check valve lds in pilotpressure line ,lili

Means responsive to the position of the plunger preferably is providedto actuate the solenoid N7 for the'high speed shot. This means maycomprise a switch (not shown) adjustably positioned to trip as theplunger reaches a predetermined point near the end of its stroke. Whenthis happens, the spool ldd is shifted to the right to conneet pressurefluid to the rod end of the cylinder 53 through chamber '32 and conduit591 thereby urging the piston 52 away from the piston 37 so that thelatter is free to move the valve 2li past the selected partially openposition. Simultaneously, parallel line d@ is connected to the drain andfluid from chamber 22 may ow past needle 4l as Well as needle di?. Thus,the setting of the needle-41 determines the new rate of Opening .of thevalve 2l and the corresponding rate of plunger acceleration. The settingof the stop 42, of course, determines the amount of final opening of thevalve 21. In a manner well known in the art, a pressure intensificationsystem (not shown) may be utilized to obtain a final high-pressurecompacting of the casting.

To withdraw the plunger i3 from the bore l2 and return y the pistons 37,52 to their retracted positions, both solenoids are cle-energized andpressure uid is directed through line 3ft to the rod end of theinjection cylinder l5. Thus, the machine is in condition for the nextinjection stroke.

it will be apparent from the foregoing that the novel valve assemblyprovides a yunitary control of relatively simple construction andoperation and effective to increase the velocity or the plunger in aplurality of precisely controlled steps which are adjustable to producethe Iwide range of combinations to tit the characteristics of the metaland die being used. The plunger may be accelerated initially at acontrolled rate which effects rapid closing of the metal well withoutdanger of splattering molten metal out of the chamber. Then, theconstant velocity filling rolie rapidly fills the die cavity with asolid, steady flow of metal. Finally, the high speed shot at the end ofthe stroke completes rapid filling vof the die at a rate which may beselected according to the shape and size of the casting, uidity andtemperature of the metal, and any other pertinent factors. rl'husJ thevalve is adaptable to insure `proper control under a wide variety ofdifferent circumstances.

We claim as our invention: -l. A valve assembly including, incombination, a valve body, a hollow cylindrical sleeve threaded into arecess in said body, a partition dividing said sleeve intermediate .itsends into rst and second cylinders disposed in end-toend relation, firstand second pistons slidable respectively in said cylinders, a valvemovable back and forth in a ine conduit 3d to the pressure line liiS'and admit` passage between an open position Iand a closed position,

said valve being connected to said first piston whereby movement of theiatter in one direction shifts said valve toward said open position, ameinbersupported on one of said pistons and journaled in said partitionto terminate adjacent the other of said pistons thereby forming a stoplfor blocking sliding of said first piston when said valve is in apartially open position, means for turning said sleeve into and out ofsaid bodyt-o adjust the position of said stop relative to saidpistonthereby to Vary said partially open position, a second memberextending l through and threaded in one end of said sleeve to 1terminateadjacent and in the path of said second piston and form a second stoplimiting sliding of the second pist-on away from said first piston yandthereby determining said open position, means for turning said secondmember int-o and ont of said sleeve to vary the position of said secondstop relative to Said second piston, and rneansfor delivering pressurefluid to said Vfirst' cylinder to move said rst piston able back andforth .between an open position and a closed position, said valve beingVconnected to said' rst piston whereby movement of the latterrin onedirection shifts said valve toward said open position, a membersupported on one of said'pistons and extending through said partition toterminate adjacent tbev'oitller of said pistons thereby forming a stopfor blockirigsliding o' said first piston when said valve is in apartially open position, means for delivering ressnre fluid to saidiirst cylinder to move said first piston in said one direction .and saidvalve into said partialiy open position and .thereatter to said secondcylinder to move said second piston away from said iirst piston, asecond member supported on said sleeve' and disposed in the path of saidsecond piston to form a second stop limiting sliding of the secondpiston away from said first piston, rneans adjustably positioningsaidrsleeve .axially in said -body to vary Vthe position of said firststop relative to said first piston, and meansadjustably positioning saidsecond member axially oflsad sleeve to vary the'position of said secondstop relative to said second piston.

Whalen Sept. l2, 1933 1,956,906 vMileaelson 'May 1,1934 '2,765,898Tydernan d Oct. 9, 1956

1. A VALVE ASSEMBLY INCLUDING IN COMBINATION, A VALVE BODY, A HOLLOWCYLINDRICAL SLEEVE THREADED INTO A RECESS IN SAID BODY, A PARTITIONDIVIDING SAID SLEEVE INTERMEDIATE ITS ENDS INTO FIRST AND SECONDCYLINDERS DISPOSED IN END-TOEND RELATION, FIRST AND SECOND PISTONSSLIDABLE RESPECTIVELY IN SAID CYLINDERS, A VALVE MOVABLE BACK AND FORTHIN A PASSAGE BETWEEN AN OPEN POSITION AND A CLOSED POSITION, SAID VALVEBEING CONNECTED TO SAID FIRST PISTON WHEREBY MOVEMENT OF THE LATTER INONE DIRECTION SHIFTS SAID VALVE TOWARD SAID OPEN POSITION, A MEMBERSUPPORTED ON ONE OF SAID PISTONS AND JOURNALED IN SAID PARTITION TOTERMINATE ADJACENT THE OTHER OF SAID PISTONS THEREBY FORMING A STOP FORBLOCKING SLIDING OF SAID FIRST PISTON WHEN SAID VALVE IS IN A PARTIALLYOPEN POSITION, MEANS FOR TURNING SAID SLEEVE INTO AND OUT OF SAID BODYTO ADJUST THE POSITION OF SAID STOP RELATIVE TO SAID PISTON THEREBY TOVARY SAID PARTIALLY OPEN POSITION, A SECOND MEMBER EXTENDING THROUGH ANDTHREADED IN ONE END OF SAID SLEEVE TO TERMINATE ADJACENT AND IN THE PATHOF SAID SECOND PISTON AND FORM A SECOND STOP LIMITING SLIDING OF THESECOND PISTON AWAY FROM SAID FIRST PISTON AND THEREBY DETERMINING SAIDOPEN POSITION, MEANS FOR TURNING SAID SECOND MEMBER INTO AND OUT OF SAIDSLEEVE TO VARY THE POSITION OF SAID SECOND STOP RELATIVE TO SAID SECONDPISTON, AND MEANS FOR DELIVERING PRESSURE FLUID TO SAID FIRST CYLINDERTO MOVE SAID PISTON AGAINST SAID FIRST STOP AND THEREAFTER TO SAIDSECOND CYLINDER TO MOVE SAID SECOND PISTON AGAINST SAID SECOND STOPWHEREBY SAID VALVE IS SHIFTED INTO SAID OPEN POSITION.